//==========================================================================
// Copyright (c) 2000-2008,  Elastos, Inc.  All Rights Reserved.
//==========================================================================
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright (C) 2001-2003 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 * $Id: scan.cpp,v 1.6 2006/05/16 14:14:00 shijun Exp $
 *
 */
#include <linux/mtd/mtd.h>
#include <linux/crc32.h>
#include "nodelist.h"
#include "linux/slab.h"
#include "jffs2_misc.h"
#include "linux/sched.h"

#define DEFAULT_EMPTY_SCAN_SIZE 1024

#if defined(_INTEL) || defined(_EVC)
void inline noisy_printk(int *noise,...)
{
    va_list ap;
    char *fmt;

    va_start(ap, noise);
    fmt = va_arg(ap, char *);

    if (*(noise)) {
        printk(KERN_NOTICE);
        vkprintf(fmt, ap);
        (*(noise))--;
        if (!(*(noise))) {
            printk(KERN_NOTICE "Further such events for this erase block will "
                            "not be printed\n");
        }
    }

    va_end(ap);
}

#define DIRTY_SPACE(x) do { uint32_t _x = (x); \
        c->free_size -= _x; c->dirty_size += _x; \
        jeb->free_size -= _x; jeb->dirty_size += _x; \
        } while(0)
#define USED_SPACE(x) do { uint32_t _x = (x); \
        c->free_size -= _x; c->used_size += _x; \
        jeb->free_size -= _x; jeb->used_size += _x; \
        } while(0)
#define UNCHECKED_SPACE(x) do { uint32_t  _x = (x); \
        c->free_size -= _x; c->unchecked_size += _x; \
        jeb->free_size -= _x; jeb->unchecked_size += _x; \
        } while(0)

#else /* defined(_INTEL) || defined(_EVC) */
#define noisy_printk(noise, args...) do { \
    if (*(noise)) { \
        printk(KERN_NOTICE args); \
         (*(noise))--; \
         if (!(*(noise))) { \
             printk(KERN_NOTICE "Further such events for this erase block will not be printed\n"); \
         } \
    } \
} while(0)

#define DIRTY_SPACE(x) do { typeof(x) _x = (x); \
        c->free_size -= _x; c->dirty_size += _x; \
        jeb->free_size -= _x ; jeb->dirty_size += _x; \
        }while(0)
#define USED_SPACE(x) do { typeof(x) _x = (x); \
        c->free_size -= _x; c->used_size += _x; \
        jeb->free_size -= _x ; jeb->used_size += _x; \
        }while(0)
#define UNCHECKED_SPACE(x) do { typeof(x) _x = (x); \
        c->free_size -= _x; c->unchecked_size += _x; \
        jeb->free_size -= _x ; jeb->unchecked_size += _x; \
        }while(0)

#endif /* defined(_INTEL) || defined(_EVC) */

static uint32_t pseudo_random;

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb, unsigned char *buf,
                uint32_t buf_size);

/* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
 * Returning an error will abort the mount - bad checksums etc. should just mark the space
 * as dirty.
 */
static int jffs2_scan_inode_node(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb, struct jffs2_raw_inode *ri,
                uint32_t ofs);
static int jffs2_scan_dirent_node(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb, struct jffs2_raw_dirent *rd,
                uint32_t ofs);

#define BLK_STATE_ALLFF  0
#define BLK_STATE_CLEAN  1
#define BLK_STATE_PARTDIRTY 2
#define BLK_STATE_CLEANMARKER 3
#define BLK_STATE_ALLDIRTY 4
#define BLK_STATE_BADBLOCK 5

static inline int min_free(struct jffs2_sb_info *c)
{
    uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER

    if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
        return c->wbuf_pagesize;
#endif

    return min;
}

static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size)
{
    if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
        return sector_size;
    else
        return DEFAULT_EMPTY_SCAN_SIZE;
}

int jffs2_scan_medium(struct jffs2_sb_info *c)
{
    int ret;
    uint32_t i;
    uint32_t empty_blocks = 0, bad_blocks = 0;
    unsigned char *flashbuf = NULL;
    uint32_t buf_size = 0;
#ifndef __ELAOS

    size_t pointlen;

    if (c->mtd->point) {
        ret = c->mtd->point (c->mtd, 0, c->mtd->size, &pointlen, &flashbuf);
        if (!ret && pointlen < c->mtd->size) {
            /* Don't muck about if it won't let us point to the whole flash */
            D1(printk(KERN_DEBUG "MTD point returned len too short: 0x%zx\n",
                            pointlen));
            c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
            flashbuf = NULL;
        }
        if (ret)
            D1(printk(KERN_DEBUG "MTD point failed %d\n", ret));
    }
#endif
    if (!flashbuf) {
        /* For NAND it's quicker to read a whole eraseblock at a time,
           apparently */
        if (jffs2_cleanmarker_oob(c))
            buf_size = c->sector_size;
        else
            buf_size = PAGE_SIZE;

        /* Respect kmalloc limitations */
        if (buf_size > 128*1024)
            buf_size = 128*1024;

        D1(printk(KERN_DEBUG "Allocating readbuf of %d bytes\n", buf_size));
        flashbuf = (unsigned char *)kmalloc(buf_size, GFP_KERNEL);
        if (!flashbuf)
            return ENOMEM;
    }

    for (i = 0; i < c->nr_blocks; i++) {
        struct jffs2_eraseblock *jeb = &c->blocks[i];

        ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
                        buf_size);

        if (ret < 0)
            goto out;

        jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

        /* Now decide which list to put it on */
        switch (ret) {
            case BLK_STATE_ALLFF:
            /*
             * Empty block.   Since we can't be sure it 
             * was entirely erased, we just queue it for erase
             * again.  It will be marked as such when the erase
             * is complete.  Meanwhile we still count it as empty
             * for later checks.
             */
                empty_blocks++;
                list_add(&jeb->list, &c->erase_pending_list);
                c->nr_erasing_blocks++;
                break;

            case BLK_STATE_CLEANMARKER:
            /* Only a CLEANMARKER node is valid */
                if (!jeb->dirty_size) {
                /* It's actually free */
                    list_add(&jeb->list, &c->free_list);
                    c->nr_free_blocks++;
                }
                else {
                /* Dirt */
                    D1(printk(KERN_DEBUG "Adding all-dirty block at 0x%08x "
                                    "to erase_pending_list\n", jeb->offset));
                    list_add(&jeb->list, &c->erase_pending_list);
                    c->nr_erasing_blocks++;
                }
                break;

            case BLK_STATE_CLEAN:
            /* Full (or almost full) of clean data. Clean list */
                list_add(&jeb->list, &c->clean_list);
                break;

            case BLK_STATE_PARTDIRTY:
            /* Some data, but not full. Dirty list. */
            /* We want to remember the block with most free space
               and stick it in the 'nextblock' position to start writing to it. */
                if (jeb->free_size > (uint32_t)min_free(c) &&
                    (!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
                /* Better candidate for the next writes to go to */
                    if (c->nextblock) {
                        c->nextblock->dirty_size += c->nextblock->free_size +
                            c->nextblock->wasted_size;
                        c->dirty_size += c->nextblock->free_size +
                            c->nextblock->wasted_size;
                        c->free_size -= c->nextblock->free_size;
                        c->wasted_size -= c->nextblock->wasted_size;
                        c->nextblock->free_size = c->nextblock->wasted_size = 0;
                        if (VERYDIRTY(c, c->nextblock->dirty_size)) {
                            list_add(&c->nextblock->list, &c->very_dirty_list);
                        }
                        else {
                            list_add(&c->nextblock->list, &c->dirty_list);
                        }
                    }
                    c->nextblock = jeb;
                }
                else {
                    jeb->dirty_size += jeb->free_size + jeb->wasted_size;
                    c->dirty_size += jeb->free_size + jeb->wasted_size;
                    c->free_size -= jeb->free_size;
                    c->wasted_size -= jeb->wasted_size;
                    jeb->free_size = jeb->wasted_size = 0;
                    if (VERYDIRTY(c, jeb->dirty_size)) {
                        list_add(&jeb->list, &c->very_dirty_list);
                    }
                    else {
                        list_add(&jeb->list, &c->dirty_list);
                    }
                }
                break;

            case BLK_STATE_ALLDIRTY:
            /* Nothing valid - not even a clean marker. Needs erasing. */
            /* For now we just put it on the erasing list. We'll start the erases later */
                D1(printk(KERN_NOTICE "JFFS2: Erase block at 0x%08x is not"
                                " formatted. It will be erased\n", jeb->offset));
                list_add(&jeb->list, &c->erase_pending_list);
                c->nr_erasing_blocks++;
                break;

            case BLK_STATE_BADBLOCK:
                D1(printk(KERN_NOTICE "JFFS2: Block at 0x%08x is bad\n",
                                jeb->offset));
                list_add(&jeb->list, &c->bad_list);
                c->bad_size += c->sector_size;
                c->free_size -= c->sector_size;
                bad_blocks++;
                break;
            default:
                printk(KERN_WARNING "jffs2_scan_medium(): unknown block state\n");
                BUG();
        }
    }

    /* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
    if (c->nextblock && (c->nextblock->dirty_size)) {
        c->nextblock->wasted_size += c->nextblock->dirty_size;
        c->wasted_size += c->nextblock->dirty_size;
        c->dirty_size -= c->nextblock->dirty_size;
        c->nextblock->dirty_size = 0;
    }
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
    if (!jffs2_can_mark_obsolete(c) && c->nextblock
            && (c->nextblock->free_size & (c->wbuf_pagesize-1))) {
        /* If we're going to start writing into a block which already
           contains data, and the end of the data isn't page-aligned,
           skip a little and align it. */

        uint32_t skip = c->nextblock->free_size & (c->wbuf_pagesize-1);

        D1(printk(KERN_DEBUG "jffs2_scan_medium(): Skipping %d bytes in"
                        " nextblock to ensure page alignment\n", skip));
        c->nextblock->wasted_size += skip;
        c->wasted_size += skip;

        c->nextblock->free_size -= skip;
        c->free_size -= skip;
    }
#endif
    if (c->nr_erasing_blocks) {
        if (!c->used_size
                && ((c->nr_free_blocks + empty_blocks + bad_blocks) != c->nr_blocks
                || bad_blocks == c->nr_blocks)) {
            printk(KERN_NOTICE "Cowardly refusing to erase blocks on filesystem"
                            " with no valid JFFS2 nodes\n");
            printk(KERN_NOTICE "c->used_size %d, free_blocks %d, empty_blocks %d,"
                            " bad_blocks %d, c->nr_blocks %d\n", c->used_size,
                            c->nr_free_blocks,empty_blocks,bad_blocks,c->nr_blocks);
            ret = EIO;
            goto out;
        }
        jffs2_erase_pending_trigger(c);
    }
    ret = 0;
out:
    if (buf_size)
        kfree(flashbuf);
#ifndef __ELAOS

    else
        c->mtd->unpoint(c->mtd, flashbuf, 0, c->mtd->size);
#endif

    return ret;
}

static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, unsigned char *buf,
                uint32_t ofs, uint32_t len)
{
    int ret;
    size_t retlen;

    ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
    if (ret) {
        D1(printk(KERN_WARNING "mtd->read(0x%x bytes from 0x%x) returned %d\n",
                        len, ofs, ret));
        return ret;
    }
    if (retlen < len) {
        D1(printk(KERN_WARNING "Read at 0x%x gave only 0x%zx bytes\n",
                        ofs, retlen));
        return EIO;
    }
    D2(printk(KERN_DEBUG "Read 0x%x bytes from 0x%08x into buf\n", len, ofs));
    D2(printk(KERN_DEBUG "000: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x"
                    " %02x %02x %02x %02x %02x %02x\n", buf[0], buf[1], buf[2],
                    buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9], buf[10],
                    buf[11], buf[12], buf[13], buf[14], buf[15]));
    return 0;
}

static int jffs2_scan_eraseblock(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
                unsigned char *buf, uint32_t buf_size)
{
    struct jffs2_unknown_node *node;
    struct jffs2_unknown_node crcnode;
    uint32_t ofs, prevofs;
    uint32_t hdr_crc, buf_ofs, buf_len;
    int err;
    int noise = 0;
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER

    int cleanmarkerfound = 0;
#endif

    ofs = jeb->offset;
    prevofs = jeb->offset - 1;

    D1(printk(KERN_DEBUG "jffs2_scan_eraseblock(): Scanning block at 0x%x\n", ofs));

#ifdef CONFIG_JFFS2_FS_WRITEBUFFER

    if (jffs2_cleanmarker_oob(c)) {
        int ret = jffs2_check_nand_cleanmarker(c, jeb);
        D2(printk(KERN_NOTICE "jffs_check_nand_cleanmarker returned %d\n",ret));
        /* Even if it's not found, we still scan to see
           if the block is empty. We use this information
           to decide whether to erase it or not. */
        switch (ret) {
            case 0:
                cleanmarkerfound = 1;
                break;
            case 1:
                break;
            case 2:
                return BLK_STATE_BADBLOCK;
            case 3:
                return BLK_STATE_ALLDIRTY; /* Block has failed to erase min. once */
            default:
                return ret;
        }
    }
#endif
    buf_ofs = jeb->offset;

    if (!buf_size) {
        buf_len = c->sector_size;
    }
    else {
        buf_len = EMPTY_SCAN_SIZE(c->sector_size);
        err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
        if (err)
            return err;
    }

    /* We temporarily use 'ofs' as a pointer into the buffer/jeb */
    ofs = 0;

    /* Scan only 4KiB of 0xFF before declaring it's empty */
    while (ofs < EMPTY_SCAN_SIZE(c->sector_size) && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
        ofs += 4;

    if (ofs == EMPTY_SCAN_SIZE(c->sector_size))
    {
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
        if (jffs2_cleanmarker_oob(c)) {
            /* scan oob, take care of cleanmarker */
            int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
            D2(printk(KERN_NOTICE "jffs2_check_oob_empty returned %d\n",ret));
            switch (ret) {
            case 0:
                return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
            case 1:
                return BLK_STATE_ALLDIRTY;
            default:
                return ret;
            }
        }
#endif
        D1(printk(KERN_DEBUG "Block at 0x%08x is empty (erased)\n", jeb->offset));
        if (c->cleanmarker_size == 0)
            return BLK_STATE_CLEANMARKER; /* don't bother with re-erase */
        else
            return BLK_STATE_ALLFF; /* OK to erase if all blocks are like this */
    }
    if (ofs) {
        D1(printk(KERN_DEBUG "Free space at %08x ends at %08x\n", jeb->offset,
                  jeb->offset + ofs));
        DIRTY_SPACE(ofs);
    }

    /* Now ofs is a complete physical flash offset as it always was... */
    ofs += jeb->offset;

    noise = 10;

scan_more:
    while (ofs < jeb->offset + c->sector_size) {

        jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

        cond_resched();

        if (ofs & 3) {
            printk(KERN_WARNING "Eep. ofs 0x%08x not word-aligned!\n", ofs);
            ofs = PAD(ofs);
            continue;
        }
        if (ofs == prevofs) {
            printk(KERN_WARNING "ofs 0x%08x has already been seen. Skipping\n", ofs);
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        prevofs = ofs;

        if (jeb->offset + c->sector_size < ofs + sizeof(*node)) {
            D1(printk(KERN_DEBUG "Fewer than %zd bytes left to end of block."
                            " (%x+%x<%x+%zx) Not reading\n",
                            sizeof(struct jffs2_unknown_node), jeb->offset,
                            c->sector_size, ofs, sizeof(*node)));
            DIRTY_SPACE((jeb->offset + c->sector_size)-ofs);
            break;
        }

        if (buf_ofs + buf_len < ofs + sizeof(*node)) {
            buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
            D1(printk(KERN_DEBUG "Fewer than %zd bytes (node header) left to"
                            " end of buf. Reading 0x%x at 0x%08x\n",
                            sizeof(struct jffs2_unknown_node), buf_len, ofs));
            err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
            if (err)
                return err;
            buf_ofs = ofs;
        }

        node = (struct jffs2_unknown_node *)&buf[ofs-buf_ofs];

        if (*(uint32_t *)(&buf[ofs-buf_ofs]) == 0xffffffff) {
            uint32_t inbuf_ofs;
            uint32_t empty_start;

            empty_start = ofs;
            ofs += 4;

            D1(printk(KERN_DEBUG "Found empty flash at 0x%08x\n", ofs));
more_empty:
            inbuf_ofs = ofs - buf_ofs;
            while (inbuf_ofs < buf_len) {
                if (*(uint32_t *)(&buf[inbuf_ofs]) != 0xffffffff) {
                    printk(KERN_WARNING "Empty flash at 0x%08x ends at 0x%08x\n",
                           empty_start, ofs);
                    DIRTY_SPACE(ofs-empty_start);
                    goto scan_more;
                }

                inbuf_ofs+=4;
                ofs += 4;
            }
            /* Ran off end. */
            D1(printk(KERN_DEBUG "Empty flash to end of buffer at 0x%08x\n", ofs));

            /* If we're only checking the beginning of a block with a cleanmarker,
               bail now */
            if (buf_ofs == jeb->offset
                    && jeb->used_size == PAD(c->cleanmarker_size)
                    && c->cleanmarker_size && !jeb->dirty_size
                    && !jeb->first_node->next_phys) {
                D1(printk(KERN_DEBUG "%d bytes at start of block seems clean... "
                                "assuming all clean\n",
                                EMPTY_SCAN_SIZE(c->sector_size)));
                return BLK_STATE_CLEANMARKER;
            }

            /* See how much more there is to read in this eraseblock... */
            buf_len = min_t(uint32_t, buf_size, jeb->offset + c->sector_size - ofs);
            if (!buf_len) {
                /* No more to read. Break out of main loop without marking
                   this range of empty space as dirty (because it's not) */
                D1(printk(KERN_DEBUG "Empty flash at %08x runs to end of block."
                                " Treating as free_space\n", empty_start));
                break;
            }
            D1(printk(KERN_DEBUG "Reading another 0x%x at 0x%08x\n", buf_len, ofs));
            err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
            if (err)
                return err;
            buf_ofs = ofs;
            goto more_empty;
        }

        if (ofs == jeb->offset && je16_to_cpu(node->magic) == KSAMTIB_CIGAM_2SFFJ) {
            printk(KERN_WARNING "Magic bitmask is backwards at offset 0x%08x."
                            " Wrong endian filesystem?\n", ofs);
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        if (je16_to_cpu(node->magic) == JFFS2_DIRTY_BITMASK) {
            D1(printk(KERN_DEBUG "Dirty bitmask at 0x%08x\n", ofs));
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        if (je16_to_cpu(node->magic) == JFFS2_OLD_MAGIC_BITMASK) {
            printk(KERN_WARNING "Old JFFS2 bitmask found at 0x%08x\n", ofs);
            printk(KERN_WARNING "You cannot use older JFFS2 filesystems with"
                            " newer kernels\n");
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        if (je16_to_cpu(node->magic) != JFFS2_MAGIC_BITMASK) {
            /* OK. We're out of possibilities. Whinge and move on */
            noisy_printk(&noise, "jffs2_scan_eraseblock(): Magic bitmask"
                            " 0x%04x not found at 0x%08x: 0x%04x instead\n",
                            JFFS2_MAGIC_BITMASK, ofs, je16_to_cpu(node->magic));
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }
        /* We seem to have a node of sorts. Check the CRC */
        crcnode.magic = node->magic;
        crcnode.nodetype = cpu_to_je16(
                        je16_to_cpu(node->nodetype) | JFFS2_NODE_ACCURATE);
        crcnode.totlen = node->totlen;
        hdr_crc = crc32(0, &crcnode, sizeof(crcnode)-4);

        if (hdr_crc != je32_to_cpu(node->hdr_crc)) {
            noisy_printk(&noise, "jffs2_scan_eraseblock(): Node at 0x%08x "
                            "{0x%04x, 0x%04x, 0x%08x) has invalid CRC 0x%08x"
                            " (calculated 0x%08x)\n", ofs,
                            je16_to_cpu(node->magic),
                            je16_to_cpu(node->nodetype),
                            je32_to_cpu(node->totlen),
                            je32_to_cpu(node->hdr_crc), hdr_crc);
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }

        if (ofs + je32_to_cpu(node->totlen) >
            jeb->offset + c->sector_size) {
            /* Eep. Node goes over the end of the erase block. */
            printk(KERN_WARNING "Node at 0x%08x with length 0x%08x would run"
                            " over the end of the erase block\n", ofs,
                            je32_to_cpu(node->totlen));
            printk(KERN_WARNING "Perhaps the file system was created with the"
                            " wrong erase size?\n");
            DIRTY_SPACE(4);
            ofs += 4;
            continue;
        }

        if (!(je16_to_cpu(node->nodetype) & JFFS2_NODE_ACCURATE)) {
            /* Wheee. This is an obsoleted node */
            D2(printk(KERN_DEBUG "Node at 0x%08x is obsolete. Skipping\n", ofs));
            DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
            ofs += PAD(je32_to_cpu(node->totlen));
            continue;
        }

        switch (je16_to_cpu(node->nodetype)) {
            case JFFS2_NODETYPE_INODE:
                if (buf_ofs + buf_len < ofs + sizeof(struct jffs2_raw_inode)) {
                    buf_len = min_t(uint32_t, buf_size,
                    jeb->offset + c->sector_size - ofs);
                    D1(printk(KERN_DEBUG "Fewer than %zd bytes (inode node) "
                                    "left to end of buf. Reading 0x%x at 0x%08x\n",
                                    sizeof(struct jffs2_raw_inode), buf_len, ofs));
                    err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
                    if (err)
                        return err;
                    buf_ofs = ofs;
                    node = (struct jffs2_unknown_node *)buf;
                }
                err = jffs2_scan_inode_node(c, jeb,
                                (struct jffs2_raw_inode *)node, ofs);
                if (err)
                    return err;
                ofs += PAD(je32_to_cpu(node->totlen));
                break;

            case JFFS2_NODETYPE_DIRENT:
                if (buf_ofs + buf_len < ofs + je32_to_cpu(node->totlen)) {
                    buf_len = min_t(uint32_t, buf_size,
                                    jeb->offset + c->sector_size - ofs);
                    D1(printk(KERN_DEBUG "Fewer than %d bytes (dirent node)"
                                    " left to end of buf. Reading 0x%x at 0x%08x\n",
                                    je32_to_cpu(node->totlen), buf_len, ofs));
                    err = jffs2_fill_scan_buf(c, buf, ofs, buf_len);
                    if (err)
                        return err;
                    buf_ofs = ofs;
                    node = (struct jffs2_unknown_node *)buf;
                }
                err = jffs2_scan_dirent_node(c, jeb,
                                (struct jffs2_raw_dirent *)node, ofs);
                if (err)
                    return err;
                ofs += PAD(je32_to_cpu(node->totlen));
                break;

            case JFFS2_NODETYPE_CLEANMARKER:
                D1(printk(KERN_DEBUG "CLEANMARKER node found at 0x%08x\n", ofs));
                if (je32_to_cpu(node->totlen) != c->cleanmarker_size) {
                    printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x has"
                                    " totlen 0x%x != normal 0x%x\n",
                       ofs, je32_to_cpu(node->totlen), c->cleanmarker_size);
                    DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
                    ofs += PAD(sizeof(struct jffs2_unknown_node));
                }
                else if (jeb->first_node) {
                    printk(KERN_NOTICE "CLEANMARKER node found at 0x%08x, not "
                                    "first node in block (0x%08x)\n", ofs,
                                    jeb->offset);
                    DIRTY_SPACE(PAD(sizeof(struct jffs2_unknown_node)));
                    ofs += PAD(sizeof(struct jffs2_unknown_node));
                }
                else {
                    struct jffs2_raw_node_ref *marker_ref = 
                        jffs2_alloc_raw_node_ref();
                    if (!marker_ref) {
                        printk(KERN_NOTICE "Failed to allocate node ref "
                                        "for clean marker\n");
                        return ENOMEM;
                    }
                    marker_ref->next_in_ino = NULL;
                    marker_ref->next_phys = NULL;
                    marker_ref->flash_offset = ofs | REF_NORMAL;
                    marker_ref->__totlen = c->cleanmarker_size;
                    jeb->first_node = jeb->last_node = marker_ref;

                    USED_SPACE(PAD(c->cleanmarker_size));
                    ofs += PAD(c->cleanmarker_size);
                }
                break;

            case JFFS2_NODETYPE_PADDING:
                DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
                ofs += PAD(je32_to_cpu(node->totlen));
                break;

            default:
                switch (je16_to_cpu(node->nodetype) & JFFS2_COMPAT_MASK) {
                    case JFFS2_FEATURE_ROCOMPAT:
                        printk(KERN_NOTICE "Read-only compatible feature node"
                                        " (0x%04x) found at offset 0x%08x\n",
                                        je16_to_cpu(node->nodetype), ofs);
                        c->flags |= JFFS2_SB_FLAG_RO;
                        if (!(jffs2_is_readonly(c)))
                            return EROFS;
                        DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
                        ofs += PAD(je32_to_cpu(node->totlen));
                        break;

                    case JFFS2_FEATURE_INCOMPAT:
                        printk(KERN_NOTICE "Incompatible feature node (0x%04x)"
                                        " found at offset 0x%08x\n", 
                                        je16_to_cpu(node->nodetype), ofs);
                        return EINVAL;

                    case JFFS2_FEATURE_RWCOMPAT_DELETE:
                        D1(printk(KERN_NOTICE "Unknown but compatible feature"
                                    " node (0x%04x) found at offset 0x%08x\n",
                                    je16_to_cpu(node->nodetype), ofs));
                        DIRTY_SPACE(PAD(je32_to_cpu(node->totlen)));
                        ofs += PAD(je32_to_cpu(node->totlen));
                        break;

                    case JFFS2_FEATURE_RWCOMPAT_COPY:
                        D1(printk(KERN_NOTICE "Unknown but compatible feature"
                                    " node (0x%04x) found at offset 0x%08x\n",
                                    je16_to_cpu(node->nodetype), ofs));
                        USED_SPACE(PAD(je32_to_cpu(node->totlen)));
                        ofs += PAD(je32_to_cpu(node->totlen));
                        break;
                }
        }
    }

    D1(printk(KERN_DEBUG "Block at 0x%08x: free 0x%08x, dirty 0x%08x,"
                    " unchecked 0x%08x, used 0x%08x\n", jeb->offset,
                    jeb->free_size, jeb->dirty_size, jeb->unchecked_size,
                    jeb->used_size));

    /* mark_node_obsolete can add to wasted !! */
    if (jeb->wasted_size) {
        jeb->dirty_size += jeb->wasted_size;
        c->dirty_size += jeb->wasted_size;
        c->wasted_size -= jeb->wasted_size;
        jeb->wasted_size = 0;
    }

    if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size)
            && !jeb->dirty_size
            && (!jeb->first_node
            || !jeb->first_node->next_phys))
        return BLK_STATE_CLEANMARKER;
    /* move blocks with max 4 byte dirty space to cleanlist */
    else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
        c->dirty_size -= jeb->dirty_size;
        c->wasted_size += jeb->dirty_size;
        jeb->wasted_size += jeb->dirty_size;
        jeb->dirty_size = 0;
        return BLK_STATE_CLEAN;
    }
    else if (jeb->used_size || jeb->unchecked_size)
        return BLK_STATE_PARTDIRTY;
    else
        return BLK_STATE_ALLDIRTY;
}

static struct jffs2_inode_cache *jffs2_scan_make_ino_cache(
                struct jffs2_sb_info *c, uint32_t ino)
{
    struct jffs2_inode_cache *ic;

    ic = jffs2_get_ino_cache(c, ino);
    if (ic)
        return ic;

    if (ino > c->highest_ino)
        c->highest_ino = ino;

    ic = jffs2_alloc_inode_cache();
    if (!ic) {
        printk(KERN_NOTICE "jffs2_scan_make_inode_cache(): allocation of"
                        " inode cache failed\n");
        return NULL;
    }
    memset(ic, 0, sizeof(*ic));

    ic->ino = ino;
    ic->nodes = (struct jffs2_raw_node_ref *)ic;
    jffs2_add_ino_cache(c, ic);
    if (ino == 1)
        ic->nlink = 1;
    return ic;
}

static int jffs2_scan_inode_node(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb,
                struct jffs2_raw_inode *ri, uint32_t ofs)
{
    struct jffs2_raw_node_ref *raw;
    struct jffs2_inode_cache *ic;
    uint32_t ino = je32_to_cpu(ri->ino);

    D1(printk(KERN_DEBUG "jffs2_scan_inode_node(): Node at 0x%08x\n", ofs));

    /* We do very little here now. Just check the ino# to which we should attribute
       this node; we can do all the CRC checking etc. later. There's a tradeoff here -- 
       we used to scan the flash once only, reading everything we want from it into
       memory, then building all our in-core data structures and freeing the extra
       information. Now we allow the first part of the mount to complete a lot quicker,
       but we have to go _back_ to the flash in order to finish the CRC checking, etc. 
       Which means that the _full_ amount of time to get to proper write mode with GC
       operational may actually be _longer_ than before. Sucks to be me. */

    raw = jffs2_alloc_raw_node_ref();
    if (!raw) {
        printk(KERN_NOTICE "jffs2_scan_inode_node(): allocation of node"
                        " reference failed\n");
        return ENOMEM;
    }

    ic = jffs2_get_ino_cache(c, ino);
    if (!ic) {
        /* Inocache get failed. Either we read a bogus ino# or it's just
           genuinely the
           first node we found for this inode. Do a CRC check to protect
           against the former
           case */
        uint32_t crc = crc32(0, ri, sizeof(*ri)-8);

        if (crc != je32_to_cpu(ri->node_crc)) {
            printk(KERN_NOTICE "jffs2_scan_inode_node(): CRC failed on node at"
                            " 0x%08x: Read 0x%08x, calculated 0x%08x\n",
                            ofs, je32_to_cpu(ri->node_crc), crc);
            /* We believe totlen because the CRC on the node _header_ was OK,
               just the node itself failed. */
            DIRTY_SPACE(PAD(je32_to_cpu(ri->totlen)));
            jffs2_free_raw_node_ref(raw);
            return 0;
        }
        ic = jffs2_scan_make_ino_cache(c, ino);
        if (!ic) {
            jffs2_free_raw_node_ref(raw);
            return ENOMEM;
        }
    }

    /* Wheee. It worked */

    raw->flash_offset = ofs | REF_UNCHECKED;
    raw->__totlen = PAD(je32_to_cpu(ri->totlen));
    raw->next_phys = NULL;
    raw->next_in_ino = ic->nodes;

    ic->nodes = raw;
    if (!jeb->first_node)
        jeb->first_node = raw;
    if (jeb->last_node)
        jeb->last_node->next_phys = raw;
    jeb->last_node = raw;

    D1(printk(KERN_DEBUG "Node is ino #%u, version %d. Range 0x%x-0x%x\n",
              je32_to_cpu(ri->ino), je32_to_cpu(ri->version),
              je32_to_cpu(ri->offset),
              je32_to_cpu(ri->offset)+je32_to_cpu(ri->dsize)));

    pseudo_random += je32_to_cpu(ri->version);

    UNCHECKED_SPACE(PAD(je32_to_cpu(ri->totlen)));
    return 0;
}

static int jffs2_scan_dirent_node(struct jffs2_sb_info *c,
                struct jffs2_eraseblock *jeb,
                struct jffs2_raw_dirent *rd, uint32_t ofs)
{
    struct jffs2_raw_node_ref *raw;
    struct jffs2_full_dirent *fd;
    struct jffs2_inode_cache *ic;
    uint32_t crc;

    D1(printk(KERN_DEBUG "jffs2_scan_dirent_node(): Node at 0x%08x\n", ofs));

    /* We don't get here unless the node is still valid, so we don't have to
       mask in the ACCURATE bit any more. */
    crc = crc32(0, rd, sizeof(*rd)-8);

    if (crc != je32_to_cpu(rd->node_crc)) {
        printk(KERN_NOTICE "jffs2_scan_dirent_node(): Node CRC failed on node "
                        "at 0x%08x: Read 0x%08x, calculated 0x%08x\n",
                        ofs, je32_to_cpu(rd->node_crc), crc);
        /* We believe totlen because the CRC on the node _header_ was OK, just 
           the node itself failed. */
        DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
        return 0;
    }

    pseudo_random += je32_to_cpu(rd->version);

    fd = jffs2_alloc_full_dirent(rd->nsize+1);
    if (!fd) {
        return ENOMEM;
    }
    memcpy(&fd->name, rd->name, rd->nsize);
    fd->name[rd->nsize] = 0;

    crc = crc32(0, fd->name, rd->nsize);
    if (crc != je32_to_cpu(rd->name_crc)) {
        printk(KERN_NOTICE "jffs2_scan_dirent_node(): Name CRC failed on node at"
                        " 0x%08x: Read 0x%08x, calculated 0x%08x\n",
                        ofs, je32_to_cpu(rd->name_crc), crc);
        D1(printk(KERN_NOTICE "Name for which CRC failed is (now) '%s', ino #%d\n",
                        fd->name, je32_to_cpu(rd->ino)));
        jffs2_free_full_dirent(fd);
        /* FIXME: Why do we believe totlen? */
        /* We believe totlen because the CRC on the node _header_ was OK, just
           the name failed. */
        DIRTY_SPACE(PAD(je32_to_cpu(rd->totlen)));
        return 0;
    }
    raw = jffs2_alloc_raw_node_ref();
    if (!raw) {
        jffs2_free_full_dirent(fd);
        printk(KERN_NOTICE "jffs2_scan_dirent_node(): allocation of node"
                        " reference failed\n");
        return ENOMEM;
    }
    ic = jffs2_scan_make_ino_cache(c, je32_to_cpu(rd->pino));
    if (!ic) {
        jffs2_free_full_dirent(fd);
        jffs2_free_raw_node_ref(raw);
        return ENOMEM;
    }

    raw->__totlen = PAD(je32_to_cpu(rd->totlen));
    raw->flash_offset = ofs | REF_PRISTINE;
    raw->next_phys = NULL;
    raw->next_in_ino = ic->nodes;
    ic->nodes = raw;
    if (!jeb->first_node)
        jeb->first_node = raw;
    if (jeb->last_node)
        jeb->last_node->next_phys = raw;
    jeb->last_node = raw;

    fd->raw = raw;
    fd->next = NULL;
    fd->version = je32_to_cpu(rd->version);
    fd->ino = je32_to_cpu(rd->ino);
    fd->nhash = full_name_hash(fd->name, rd->nsize);
    fd->type = rd->type;
    USED_SPACE(PAD(je32_to_cpu(rd->totlen)));
    jffs2_add_fd_to_list(c, fd, &ic->scan_dents);

    return 0;
}

static int count_list(struct list_head *l)
{
    uint32_t count = 0;
    struct list_head *tmp;

    list_for_each(tmp, l)
    {
        count++;
    }
    return count;
}

/* Note: This breaks if list_empty(head). I don't care. You
   might, if you copy this code and use it elsewhere :) */
static void rotate_list(struct list_head *head, uint32_t count)
{
    struct list_head *n = head->next;

    list_del(head);
    while (count--) {
        n = n->next;
    }
    list_add(head, n);
}

void jffs2_rotate_lists(struct jffs2_sb_info *c)
{
    uint32_t x;
    uint32_t rotateby;

    x = count_list(&c->clean_list);
    if (x) {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating clean_list by %d\n", rotateby));

        rotate_list((&c->clean_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of clean_list is at %08x\n",
                        list_entry(c->clean_list.next, struct jffs2_eraseblock,
                        list)->offset));
    }
    else {
        D1(printk(KERN_DEBUG "Not rotating empty clean_list\n"));
    }

    x = count_list(&c->very_dirty_list);
    if (x) {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating very_dirty_list by %d\n", rotateby));

        rotate_list((&c->very_dirty_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of very_dirty_list is at %08x\n",
                        list_entry(c->very_dirty_list.next, struct jffs2_eraseblock,
                        list)->offset));
    }
    else {
        D1(printk(KERN_DEBUG "Not rotating empty very_dirty_list\n"));
    }

    x = count_list(&c->dirty_list);
    if (x) {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating dirty_list by %d\n", rotateby));

        rotate_list((&c->dirty_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of dirty_list is at %08x\n",
                        list_entry(c->dirty_list.next, struct jffs2_eraseblock,
                        list)->offset));
    }
    else {
        D1(printk(KERN_DEBUG "Not rotating empty dirty_list\n"));
    }

    x = count_list(&c->erasable_list);
    if (x) {
        rotateby = pseudo_random % x;
        D1(printk(KERN_DEBUG "Rotating erasable_list by %d\n", rotateby));

        rotate_list((&c->erasable_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of erasable_list is at %08x\n",
                        list_entry(c->erasable_list.next, struct jffs2_eraseblock,
                        list)->offset));
    }
    else {
        D1(printk(KERN_DEBUG "Not rotating empty erasable_list\n"));
    }

    if (c->nr_erasing_blocks) {
        rotateby = pseudo_random % c->nr_erasing_blocks;
        D1(printk(KERN_DEBUG "Rotating erase_pending_list by %d\n", rotateby));

        rotate_list((&c->erase_pending_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of erase_pending_list is at %08x\n",
                        list_entry(c->erase_pending_list.next, struct jffs2_eraseblock,
                        list)->offset));
    }
    else {
        D1(printk(KERN_DEBUG "Not rotating empty erase_pending_list\n"));
    }

    if (c->nr_free_blocks) {
        rotateby = pseudo_random % c->nr_free_blocks;
        D1(printk(KERN_DEBUG "Rotating free_list by %d\n", rotateby));

        rotate_list((&c->free_list), rotateby);

        D1(printk(KERN_DEBUG "Erase block at front of free_list is at %08x\n",
                        list_entry(c->free_list.next, struct jffs2_eraseblock,
                        list)->offset));
    }
    else {
        D1(printk(KERN_DEBUG "Not rotating empty free_list\n"));
    }
}
